What causes hemoptysis in pulmonary embolism?

Causes of hemoptysis (coughing up blood) due to pulmonary embolism: 1. **Vascular wall injury**: When a pulmonary embolism occurs, the sudden increase in pulmonary arterial pressure can cause the blood vessel walls to thin or even rupture, leading to blood leakage. 2. **Blood stasis at the embolism site**: Blood stasis at the site of the embolism may cause pulmonary edema and extravasation of blood, which can enter the alveoli. 3. **Bronchial wall rupture**: Blood entering the alveoli may cause rupture of the bronchial walls, allowing blood to be expelled through the trachea as hemoptysis, typically appearing as dark red in color. Hemoptysis caused by pulmonary embolism is primarily the result of combined effects of vascular wall injury, blood stasis at the embolism site, and bronchial wall rupture. If related symptoms occur, prompt medical attention should be sought for diagnosis and treatment.